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Uzal-Varela R, Rodríguez-Rodríguez A, Lalli D, Valencia L, Maneiro M, Botta M, Iglesias E, Esteban-Gómez D, Angelovski G, Platas-Iglesias C. Endeavor toward Redox-Responsive Transition Metal Contrast Agents Based on the Cross-Bridge Cyclam Platform. Inorg Chem 2024; 63:1575-1588. [PMID: 38198518 PMCID: PMC10806912 DOI: 10.1021/acs.inorgchem.3c03486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/21/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024]
Abstract
We present the synthesis and characterization of a series of Mn(III), Co(III), and Ni(II) complexes with cross-bridge cyclam derivatives (CB-cyclam = 1,4,8,11-tetraazabicyclo[6.6.2]hexadecane) containing acetamide or acetic acid pendant arms. The X-ray structures of [Ni(CB-TE2AM)]Cl2·2H2O and [Mn(CB-TE1AM)(OH)](PF6)2 evidence the octahedral coordination of the ligands around the Ni(II) and Mn(III) metal ions, with a terminal hydroxide ligand being coordinated to Mn(III). Cyclic voltammetry studies on solutions of the [Mn(CB-TE1AM)(OH)]2+ and [Mn(CB-TE1A)(OH)]+ complexes (0.15 M NaCl) show an intricate redox behavior with waves due to the MnIII/MnIV and MnII/MnIII pairs. The Co(III) and Ni(II) complexes with CB-TE2A and CB-TE2AM show quasi-reversible features due to the CoIII/CoII or NiII/NiIII pairs. The [Co(CB-TE2AM)]3+ complex is readily reduced by dithionite in aqueous solution, as evidenced by 1H NMR studies, but does not react with ascorbate. The [Mn(CB-TE1A)(OH)]+ complex is however reduced very quickly by ascorbate following a simple kinetic scheme (k0 = k1[AH-], where [AH-] is the ascorbate concentration and k1 = 628 ± 7 M-1 s-1). The reduction of the Mn(III) complex to Mn(II) by ascorbate provokes complex dissociation, as demonstrated by 1H nuclear magnetic relaxation dispersion studies. The [Ni(CB-TE2AM)]2+ complex shows significant chemical exchange saturation transfer effects upon saturation of the amide proton signals at 71 and 3 ppm with respect to the bulk water signal.
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Affiliation(s)
- Rocío Uzal-Varela
- Centro
Interdisciplinar de Química e Bioloxía (CICA) and Departamento
de Química, Facultade de Ciencias, Universidade da Coruña, A Coruña 15071, Galicia, Spain
| | - Aurora Rodríguez-Rodríguez
- Centro
Interdisciplinar de Química e Bioloxía (CICA) and Departamento
de Química, Facultade de Ciencias, Universidade da Coruña, A Coruña 15071, Galicia, Spain
| | - Daniela Lalli
- Dipartimento
di Scienze e Innovazione Tecnologica, Magnetic Resonance Platform
(PRISMA-UPO), Universitá del Piemonte
Orientale, Viale T. Michel
11, Alessandria 15121, Italy
| | - Laura Valencia
- Departamento
de Química Inorgánica, Facultad de Ciencias, Universidade de Vigo, As Lagoas, Marcosende 36310, Pontevedra, Spain
| | - Marcelino Maneiro
- Departamento
de Química Inorgánica, Facultade de Ciencias, Campus
Terra, Universidade de Santiago de Compostela, Lugo 27002, Galicia, Spain
| | - Mauro Botta
- Dipartimento
di Scienze e Innovazione Tecnologica, Magnetic Resonance Platform
(PRISMA-UPO), Universitá del Piemonte
Orientale, Viale T. Michel
11, Alessandria 15121, Italy
| | - Emilia Iglesias
- Centro
Interdisciplinar de Química e Bioloxía (CICA) and Departamento
de Química, Facultade de Ciencias, Universidade da Coruña, A Coruña 15071, Galicia, Spain
| | - David Esteban-Gómez
- Centro
Interdisciplinar de Química e Bioloxía (CICA) and Departamento
de Química, Facultade de Ciencias, Universidade da Coruña, A Coruña 15071, Galicia, Spain
| | - Goran Angelovski
- Laboratory
of Molecular and Cellular Neuroimaging, International Center for Primate
Brain Research (ICPBR), Center for Excellence in Brain Science and
Intelligence Technology (CEBSIT), Chinese
Academy of Sciences (CAS), Shanghai 201602, PR China
| | - Carlos Platas-Iglesias
- Centro
Interdisciplinar de Química e Bioloxía (CICA) and Departamento
de Química, Facultade de Ciencias, Universidade da Coruña, A Coruña 15071, Galicia, Spain
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Garcia L, Koper MR, Mondal S, Priddle JT, Truong WA, Allbritton EMA, McAdoo AG, Cannon-Smith DJ, Funwie NL, Hoang T, Kim I, Hubin DJ, Krause JA, Oliver AG, Prior TJ, Hubin TJ. Earth Abundant Oxidation Catalysts for Removal of Contaminants of Emerging Concern from Wastewater: Homogeneous Catalytic Screening of Monomeric Complexes. Molecules 2023; 28:6466. [PMID: 37764242 PMCID: PMC10536317 DOI: 10.3390/molecules28186466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 08/28/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Twenty novel Mn, Fe, and Cu complexes of ethylene cross-bridged tetraazamacrocycles with potentially copolymerizable allyl and benzyl pendant arms were synthesized and characterized. Multiple X-ray crystal structures demonstrate the cis-folded pseudo-octahedral geometry forced by the rigidifying ethylene cross-bridge and show that two cis coordination cites are available for interaction with substrate and oxidant. The Cu complexes were used to determine kinetic stability under harsh acidic and high-temperature conditions, which revealed that the cyclam-based ligands provide superior stabilization with half-lives of many minutes or even hours in 5 M HCl at 50-90 °C. Cyclic voltammetry studies of the Fe and Mn complexes reveal reversible redox processes indicating stabilization of Fe2+/Fe3+ and Mn2+/Mn3+/Mn4+ oxidation states, indicating the likelihood of catalytic oxidation for these complexes. Finally, dye-bleaching experiments with methylene blue, methyl orange, and rhodamine B demonstrate efficient catalytic decolorization and allow selection of the most successful monomeric catalysts for copolymerization to produce future heterogeneous water purification materials.
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Affiliation(s)
- Leslie Garcia
- Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
| | - Makynna R. Koper
- Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
| | - Somrita Mondal
- Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
| | - Joshua T. Priddle
- Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
| | - William A. Truong
- Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
| | | | - Ashtyn G. McAdoo
- Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
| | - Desiray J. Cannon-Smith
- Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
| | - Neil L. Funwie
- Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
| | - Tuyet Hoang
- Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
| | - Inseo Kim
- Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
| | - David J. Hubin
- Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
| | - Jeanette A. Krause
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45220, USA
| | - Allen G. Oliver
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Timothy J. Prior
- Department of Chemistry, School of Natural Sciences, University of Hull, Kingston Upon Hull HU6 7RX, UK
| | - Timothy J. Hubin
- Department of Chemistry and Physics, Southwestern Oklahoma State University, Weatherford, OK 73096, USA
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